umlConnectTapDevice: initialize tapfd variable
umlConnectTapDevice: initialize tapfd variable

There is possibility to jump to 'cleanup' label without tapfd variable
being initialized. In the label, VIR_FORCE_CLOSE(tapfd) is called which
can have fatal consequences.

cbosdo/libvirt,rlaager/libvirt,nertpinx/libvirt,zippy2/libvirt,taget/libvirt,shugaoye/libvirt,jfehlig/libvirt,taget/libvirt,jardasgit/libvirt,nertpinx/libvirt,taget/libvirt,agx/libvirt,VenkatDatta/libvirt,zippy2/libvirt,olafhering/libvirt,zhlcindy/libvirt-1.1.4-maintain,datto/libvirt,agx/libvirt,libvirt/libvirt,VenkatDatta/libvirt,agx/libvirt,jfehlig/libvirt,cbosdo/libvirt,crobinso/libvirt,fabianfreyer/libvirt,libvirt/libvirt,fabianfreyer/libvirt,rlaager/libvirt,andreabolognani/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,zhlcindy/libvirt-1.1.4-maintain,eskultety/libvirt,zhlcindy/libvirt-1.1.4-maintain,elmarco/libvirt,agx/libvirt,datto/libvirt,datto/libvirt,libvirt/libvirt,elmarco/libvirt,andreabolognani/libvirt,andreabolognani/libvirt,cbosdo/libvirt,zippy2/libvirt,cbosdo/libvirt,jardasgit/libvirt,jardasgit/libvirt,shugaoye/libvirt,elmarco/libvirt,VenkatDatta/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,agx/libvirt,cbosdo/libvirt,eskultety/libvirt,crobinso/libvirt,zippy2/libvirt,taget/libvirt,eskultety/libvirt,zhlcindy/libvirt-1.1.4-maintain,rlaager/libvirt,eskultety/libvirt,nertpinx/libvirt,datto/libvirt,rlaager/libvirt,olafhering/libvirt,shugaoye/libvirt,elmarco/libvirt,crobinso/libvirt,rlaager/libvirt,zhlcindy/libvirt-1.1.4-maintain,nertpinx/libvirt,eskultety/libvirt,elmarco/libvirt,libvirt/libvirt,VenkatDatta/libvirt,shugaoye/libvirt,crobinso/libvirt,andreabolognani/libvirt,olafhering/libvirt,taget/libvirt,jardasgit/libvirt,nertpinx/libvirt,VenkatDatta/libvirt,jfehlig/libvirt,jfehlig/libvirt,datto/libvirt,shugaoye/libvirt,olafhering/libvirt